Carcharhinid

Requiem sharks are sharks of the family Carcharhinidae in the order Carcharhiniformes. They are migratory, live-bearing sharks of warm seas (sometimes of brackish or fresh water) and include such species as the bull shark, lemon shark, blacktip shark, and whitetip reef shark.

Family members have the usual carcharhiniform characteristics. Their eyes are round, and one or two gill slits fall over the pectoral fin base. Most species are viviparous, the young being born fully developed. They vary widely in size, from as small as adult length in the Australian sharpnose shark, up to adult length in the oceanic whitetip shark.Compagno, L.J.V
Family Carcharhinidae - Requiem sharks
in Froese, R. and D. Pauly. Editors. 2010
FishBase
World Wide Web electronic publication, version (10/2013). Scientists assume that the size and shape of their pectoral fins have the right dimensions to minimize transport cost. Requiem sharks tend to live in more tropical areas, but tend to migrate. Females release a chemical in the ocean in order to let the males know they are ready to mate. Typical mating time for these sharks is around spring to autumn.

According to the ISAF, requiem sharks are among the top five species involved in shark attacks on humans; however, "requiem shark" is not a single species, but refers, in this case, to an order of similar sharks that are often involved in incidents. ISAF prefers to use "requiem sharks" due to the difficulty in identifying individual species.

Etymology

The common name requiem shark may be related to the French word for shark, ''requin'', which is itself of disputed etymology. One derivation of the latter is from Latin ''requiem'' ("rest"), which would thereby create a cyclic etymology (''requiem-requin-requiem''), but other sources derive it from the Old French verb ''reschignier'' ("to grimace while baring teeth").

The scientific name Carcharhinidae was first proposed in 1896 by D.S. Jordan and B.W. Evermann as a subfamily of Galeidae (now replaced by "Carcharhinidae"). The term is derived from Greek (''karcharos'', sharp or jagged), and ῥί̄νη (''rhinē'', rasp); both elements describe the jagged, rasp-like skin. Rasp-like skin is typical of shark skin in general, and is not diagnostic to Carcharhinidae.

Evolutionary history

The oldest member of the family is '' Archaeogaleus lengadocensis'' from the Early Cretaceous (Valanginian) of France. Only a handful of records of the group are known from prior to the beginning of the Cenozoic. Modern carcharinid sharks have extensively diversified in coral reef habitats.

Hunting strategies

Requiem sharks are extraordinarily fast and effective hunters. Their elongated, torpedo-shaped bodies make them quick and agile swimmers, so they can easily attack any prey. Some species are continually active, while others are capable of resting motionless for extended periods on the bottom. They have a range of food sources depending on location and species, including bony fish, squid, octopus, lobster, turtles, marine mammals, seabirds, other sharks and rays; smaller species tend to select a narrow range of prey, but some very large species, especially the tiger shark (Galeocerdo cuvier), are virtually omnivorous. They are often considered the "garbage cans" of the seas because they will eat almost anything, even non-food items like trash. They are migratory hunters that follow their food source across entire oceans. They tend to be most active at night time, where their impressive eyesight can help them sneak up on unsuspecting prey. It is worth mentioning that the tiger shark, however, possibly belongs to the Galeocerdidae family. Most requiem sharks hunt alone, however some species like the whitetip reef sharks and lemon sharks are cooperative feeders and will hunt in packs through coordinated, timed attacks against their prey. Some of the species have been shown to give specialized displays when confronted by divers or other sharks, which may be indicative of aggressive or defensive threat.

Classification

The 60 species of requiem shark are grouped into 11 genera:
* Genus '' Scoliodon'' J. P. Müller & Henle, 1838
** '' Scoliodon laticaudus'' J. P. Müller & Henle, 1838 (spadenose shark)
** '' Scoliodon macrorhynchos'' Bleeker, 1852 (Pacific spadenose shark)
* Genus ''Carcharhinus'' Blainville, 1816
**'' Carcharhinus acronotus'' Poey, 1860 (blacknose shark)
** '' Carcharhinus albimarginatus'' Rüppell, 1837 (silvertip shark)
** '' Carcharhinus altimus'' S. Springer, 1950 (bignose shark)
** '' Carcharhinus amblyrhynchoides'' Whitley, 1934 (graceful shark)
** '' Carcharhinus amblyrhynchos'' Bleeker, 1856 (grey reef shark)
** '' Carcharhinus amboinensis'' J. P. Müller & Henle, 1839 (pigeye shark)
** '' Carcharhinus borneensis'' Bleeker, 1858 (Borneo shark)
** '' Carcharhinus brachyurus'' Günther, 1870 (copper shark)
** '' Carcharhinus brevipinna'' J. P. Müller & Henle, 1839 (spinner shark)
** '' Carcharhinus cautus'' Whitley, 1945 (nervous shark)
** '' Carcharhinus cerdale'' C. H. Gilbert, 1898 (Pacific smalltail shark)
** '' Carcharhinus coatesi'' Whitley, 1939 (Coates's shark)
** '' Carcharhinus dussumieri'' J. P. Müller & Henle, 1839 (whitecheek shark)
** '' Carcharhinus falciformis'' J. P. Müller & Henle, 1839 (silky shark)
** '' Carcharhinus fitzroyensis'' Whitley, 1943 (creek whaler)
** '' Carcharhinus galapagensis'' Snodgrass & Heller, 1905 (Galapagos shark)
** '' Carcharhinus hemiodon'' J. P. Müller & Henle, 1839 (Pondicherry shark)
** '' Carcharhinus humani'' W. T. White & Weigmann, 2014 (Human's whaler shark)
** '' Carcharhinus isodon'' J. P. Müller & Henle, 1839 (finetooth shark)
** '' Carcharhinus leiodon'' Garrick, 1985 (smoothtooth blacktip shark)
** '' Carcharhinus leucas'' J. P. Müller & Henle, 1839 (bull shark)
** '' Carcharhinus limbatus'' J. P. Müller & Henle, 1839 (blacktip shark)
** '' Carcharhinus longimanus'' Poey, 1861 (oceanic whitetip shark)
** '' Carcharhinus macloti'' J. P. Müller & Henle, 1839 (hardnose shark)
** '' Carcharhinus melanopterus'' Quoy & Gaimard, 1824 (blacktip reef shark)
** '' Carcharhinus obscurus'' Lesueur, 1818 (dusky shark)
** '' Carcharhinus perezi'' Poey, 1876 (Caribbean reef shark)
** '' Carcharhinus plumbeus'' Nardo, 1827 (sandbar shark)
** '' Carcharhinus porosus'' Ranzani, 1839 (smalltail shark)
** '' Carcharhinus sealei'' Pietschmann, 1913 (blackspot shark)
** '' Carcharhinus signatus'' Poey, 1868 (night shark)
** '' Carcharhinus sorrah'' J. P. Müller & Henle, 1839 (spot-tail shark)
** '' Carcharhinus tilstoni'' Whitley, 1950 (Australian blacktip shark)
** †'' Carcharhinus tingae''
** '' Carcharhinus tjutjot'' Bleeker, 1852 (Indonesian whaler shark)
** '' Carcharhinus obsolerus'' White, Kyne, and Harris, 2019 (lost shark)
* Genus '' Glyphis'' Agassiz, 1843
** '' Glyphis gangeticus'' J. P. Müller & Henle, 1839 (Ganges shark)
** '' Glyphis garricki'' Compagno, W. T. White & Last, 2008 (northern river shark)
** '' Glyphis glyphis'' J. P. Müller & Henle, 1839 (speartooth shark)
** '' Glyphis'' sp. not yet described (Mukah river shark)
* Genus '' Lamiopsis'' Gill, 1862
** '' Lamiopsis temminckii'' J. P. Müller & Henle, 1839 (broadfin shark)
** '' Lamiopsis tephrodes'' Fowler, 1905 (Borneo broadfin shark)
* Genus '' Nasolamia'' Compagno & Garrick, 1983
** '' Nasolamia velox'' C. H. Gilbert, 1898 (whitenose shark)
* Genus ''Negaprion'' Whitley, 1940
** '' Negaprion acutidens'' Rüppell, 1837 (sicklefin lemon shark)
** ''Negaprion brevirostris'' Poey, 1868 (lemon shark)
** †'' Negaprion eurybathrodon'' Blake, 1862
* Genus '' Prionace'' Cantor, 1849
** '' Prionace glauca'' Linnaeus, 1758 (blue shark)
* Genus '' Rhizoprionodon'' Whitley, 1929
** '' Rhizoprionodon acutus'' Rüppell, 1837 (milk shark)
** '' Rhizoprionodon lalandii'' J. P. Müller & Henle, 1839 (Brazilian sharpnose shark)
** '' Rhizoprionodon longurio'' D. S. Jordan & C. H. Gilbert, 1882 (Pacific sharpnose shark)
** '' Rhizoprionodon oligolinx'' V. G. Springer, 1964 (grey sharpnose shark)
** '' Rhizoprionodon porosus'' Poey, 1861 (Caribbean sharpnose shark)
** '' Rhizoprionodon taylori'' Ogilby, 1915 (Australian sharpnose shark)
** '' Rhizoprionodon terraenovae'' J. Richardson, 1836 (Atlantic sharpnose shark)
* Genus '' Loxodon'' J. P. Müller & Henle, 1838
** '' Loxodon macrorhinus'' J. P. Müller & Henle, 1839 (sliteye shark)
* Genus '' Isogomphodon'' Gill, 1862
** '' Isogomphodon oxyrhynchus'' J. P. Müller & Henle, 1839 (daggernose shark)
* Genus '' Triaenodon'' J. P. Müller & Henle, 1837
** '' Triaenodon obesus'' Rüppell, 1837 (whitetip reef shark)
* Genus †'' Physogaleus'' Cappetta, 1980
** †''Physogaleus americanus'' Case, 1994
** †''Physogaleus contortus'' Gibbes, 1849
** †''Physogaleus hemmooriensis'' Reinecke & Hoedemakers, 2006
** †''Physogaleus huberensis'' Case, 1981
** †''Physogaleus latecuspidatus'' Muller, 1999
** †''Physogaleus latus'' Storms, 1894
** †''Physogaleus maltzani'' Winkler, 1875
** †''Physogaleus onkensis'' Boulemia & Adnet, 2023
** †''Physogaleus rosehillensis'' Case & Borodin, 2000
** †''Physogaleus secundus'' Winkler, 1876
** †''Physogaleus tertius'' Winkler, 1876
† = extinct

See also

* Freshwater shark

References

Sources

External links

Requiem Shark Photo Gallery
(Bahamas)

Elasmo-research

{{Authority control

Taxa named by David Starr Jordan
Taxa named by Barton Warren Evermann
Extant Valanginian first appearances